There are two main kinds of over-the-ear headphones: Open-Back and Closed-Back. Each offer benefits and each has drawbacks. Over-the-ear headphones (or, for the terminology-loving, circumaural headphones) come in two primary flavors: open-back and closed-back. Before you sink some serious cash into a nice pair of headphones it pays to know the difference.

If you're in the market for some new headphones, especially if you're looking to make an investment in some good headphones, it's important to understand the differences.

Most headphones are "closed-back," which is to say, the outer part of the headphone cups have a hard enclosure. Take a look at above blow image, the black one (on the right), is closed-back. Open-back, as you've probably figured, leaves the back of headphone cup open. The headphones on the left are open-back.

I love it when tech terminology is simple. There are benefits to both kinds, which is where things get interesting.The small speaker drivers in headphones emit sound in both directions: towards your ears and away from your ears (as in, out towards the world). Closed-back headphones largely block the sound aimed towards the world. Open-back headphones, of course, let this sound largely go free.

In general terms, closed-back headphones are designed to isolate you from the outside world. It's just you and your music. The downside is the music is a lot more "in your head" sounding. It's less like a "band in a concert hall" and more "a band in your head". Perhaps not that extreme, but you get the idea. Again, this is generally speaking. There can be exceptions.

The downside to open-back is probably obvious: everyone can hear what you're listening to, and any ambient sound gets right in and mixes with your music. The benefit, though, is some of that sound that's headed out towards the world also gets mixed in with your music. The result is the headphone sounds significantly larger than closed-back headphones. More "open" sounding. Less like music beamed into your head, and more like music in a room. In other words, potentially more realistic.

There are some closed-back headphones that sound very open, but there is noticeably different sound to open-back headphones. Open-back headphones aren't ideal in many situations, and not everyone loves the sound. But for those that do, it can be a different headphone experience.

Open-back headphones are available at different prices, but there are fewer choices, and few cheap options.

From the appearance, our MS301 is a closed-back design. Since the drivers are isolated in a chamber, and the ear cups as well as the headband are well padded, MS301 can largely isolate you from the outside world. You could enjoy the fantastic music without any sound interference from others. In the same time, people around you could hardly hear the sound even though you turn up the volume. Nevertheless, the driver is not completely sealed and does leak some sound out the hinge-- a connection between the metal portion of the earpiece and the plastic that holds the driver and pads that is designed to swivel for comfort, which to some extent allows air to move around the driver. Hence, it is a close-back design but it also has open-back headsets'advantage.